1. Field of the Invention
The present invention relates to a protection circuit assembly and a battery pack including the same, and more particularly, to a protection circuit assembly and a battery pack including the same, which simplifies the manufacturing process and increases/improves productivity.
2. Description of the Related Art
Secondary batteries are more economical than disposable batteries since they are rechargeable.
Moreover, in recent time, since secondary batteries are getting smaller and have higher capacity, they are widely used as power sources of handheld electronic/electrical appliances such as mobile phones, camcorders and notebook computers.
Such secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries and lithium secondary batteries.
Among the secondary batteries, a lithium secondary battery is widely used due to its compact size, high capacity, high operating voltage and higher energy density per unit weight than other batteries.
The lithium secondary battery is classified into a can type and a pouch type according to the shape of an outer casing for accommodating an electrode assembly including a positive electrode plate, a negative electrode plate and a separator, and the can type may be sub-classified into a cylinder type and a prismatic type.
In the can-type lithium secondary battery, an outer casing is generally formed of a metal such as aluminum, and formed in a cylinder shape, a prism shape or a rod shape having rounded corners.
An opening is formed in an upper portion of a can, an electrode assembly is inserted into the can through the opening, and then an electrolyte is injected to fill the can.
Subsequently, the can is sealed with a cap assembly having the size and shape corresponding to the opening formed in the upper portion of the can, and thus a sealed bare cell is completed.
In the pouch-type lithium secondary battery, an outer casing has an electrode assembly on a lower surface of the pouch casing having a space for accommodating the electrode assembly.
Subsequently, an upper surface of the pouch casing covers the lower surface of the pouch casing, and sealing portions formed along edges of the upper and lower surfaces of the pouch casing are joined to each other to seal the casing, and thus a bare cell is formed.
The bare cell is electrically connected with a protection circuit board including a protection device to prevent damage to the battery due to abnormal operations such as overcharging, overdischarging or overcurrent.
In general, the bare cell and the protection circuit board are electrically connected with each other using a lead terminal, and thus a battery pack is formed.
In the prismatic-type secondary battery, an electrical connection between a bare cell and a protection circuit board is made by connecting a cap plate and an electrode terminal of the bare cell with positive and negative electrode terminals of the protection circuit board using a lead terminal.
Here, the cap plate is formed of aluminum, or an aluminum alloy, and the lead terminal is formed of nickel having high conductivity.
Since it is difficult to resistance-weld these different metals, the connection between the cap plate and the lead terminal may be made by laser welding.
Therefore, production costs increase due to such expensive laser welding.
The above information disclosed in this Related Art section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.